Regulatory Assets and Liabilities

12 Months Ended

Dec. 31, 2011

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets and Liabilities

REGULATORY ASSETS AND LIABILITIES

The following table details regulatory assets and liabilities on the consolidated balance sheets:

(in thousands)	December 31, 2011				December 31, 2010
	Current		Noncurrent		Current		Noncurrent
Regulatory assets:
Pension and postretirement assets	$	170	$	77,587	$	132	$	60,284
Accretion and depreciation for asset retirement obligation	—		13,981		—		8,681
Risk management activities	56,804		3,070		27,906		32,461
Asset removal costs, net	—		994		—		—
Enhanced stability reserve	—		—		—		3,794
Other	169		1		248		145
Total regulatory assets	$	57,143	$	95,633	$	28,286	$	105,365
Regulatory liabilities:
RSE adjustment	$	2,931	$	—	$	4,147	$	—
Unbilled service margin	22,419		—		34,197		—
Postretirement liabilities	—		—		—		754
Gas supply adjustment	12,626		—		14,990		—
Asset removal costs, net	—		—		—		6,913
Refundable negative salvage	20,269		65,646		22,336		90,504
Asset retirement obligation	—		20,785		—		11,439
Other	34		803		33		837
Total regulatory liabilities	$	58,279	$	87,234	$	75,703	$	110,447

As described in Note 2, Regulatory Matters, Alagasco's rates are established under the RSE rate-setting process and are based on average equity for the period. Alagasco's rates are not adjusted to exclude a return on its investment in regulatory assets during the recovery period.